1. Field of the Invention
The invention relates to a malfunction detecting device for a solar cell panel that detects a malfunction, such as a failure, etc., in the solar cell panel.
2. Description of the Related Art
A conventional solar cell panel malfunction detecting device is known that detects a malfunction, such as a failure, etc., in a solar cell panel based on characteristics of DC current-voltage output from the solar cell panel (see, e.g., JP-A-2006-201827).
As shown in FIG. 8A, in a solar cell power generation system, a solar cell module 81 is generally formed by connecting plural solar cell panels 82 in series. A bypass diode 84 is each provided between positive and negative terminals extending from an edge of a solar cell panel body 83 of each solar cell panel 82 (see, e.g., JP-A-11-330521).
A case where output of, e.g., the second solar cell panel body 83 from the left in the drawing is reduced due to shadow, etc., thereon is examined here. When output of a solar cell panel body 83 is reduced, this solar cell panel body 83 with reduced output becomes a resistive element of a downstream solar cell panel 82 (on the right side in the drawing). Therefore, the electric current from the downstream solar cell panel 82 bypasses the solar cell panel body 83 with reduced output and flows in the bypass diode 84 with a resistance of substantially zero as indicated by a dashed arrow in the drawing. Thus, the bypass diode 84 serves to bypass electric current from the downstream solar cell panel 82.